Major effort will be devoted to further characterization of the Ddp ATPase, both structurally and enzymatically. Structural studies planned are (a) identification of the phosphorylated amino acid residue; (b) determination of the amino acid sequence in the vicinity of the phosphorylated amino acid; (c) further purification and characterization of the non-ionic detergent solubilized enzyme; and (d) a restriction analysis of the kdp operon as a preliminary step to undertaking DNA sequence studies. Functional studies include: a) characterization of substrate and inhibitor responses of the ATPhase; b) a search for and characterization of additional partial reactions not yet known to occur such as ATP-ADP exchange, acyl phosphatase, etc.: c) kinetic analysis of the formation and decay of the phosphorylated intermediate. Preliminary studies on what are suspected to be other substrate-dependent transport ATPases in E. coli will be pursued, with a primary aim of demonstrating that these activities are due to a specific transport system.